Powerful Owls

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Listen to their distinctive ‘whoo-hoo’.

Appearance

Australia’s largest Owl with a wingspan of up to 135cm. Adult powerful owls are dark brown to grey on top with white flecks or bars. They have large yellow eyes and a comparatively small head. They are white underneath with distinctive darker v-shaped patterns throughout. 

Diet

They forage mainly in tree canopies. Prey items include arboreal marsupials such as Ringtail Possums and Sugar Gliders. 

Distribution and Habitat

Found in eastern to south-eastern Australia. They generally reside in open forest and woodlands or temperate rainforest gullies. However they have been seen throughout suburban areas adjacent to bushland and are found throughout suburbs of Sydney. They occupy large home ranges all year round which are generally centred on bushland. 

Breeding

The Owls require large tree hollows in old-growth eucalypt trees over 200 years old for their nests. They are monogamous birds and within the breeding season of April-September, will lay most commonly two eggs that the female will incubate for around 38 days while the male guards close by. 

Call

Powerful Owls have long ranging, distinctive calls. The well-known double note: “whoo-hoo” – distinctive between males and females. Female calls inflect upwards while male calls remain low or be lower on the second note. Visit here and see if you can tell the difference between the different owl calls.

Conservation Status

Listed as “Least Concern” on ICUN redlist. Conservation status in NSW: Vulnerable

The fledging of a Powerful Owl in Ku-ring-gai

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In 2016, Ku-ring-gai Council’s Natural Areas Officer, Jacob Sife, and local photographer Chris Charles set off to monitor a pair of Powerful Owls in a bushland reserve in the south-west of Ku-ring-gai. Chris had been monitoring Powerful Owls within this particular reserve for more than 10 years and had not observed a successfully fledged chick since 2010.

In 2015 a single chick failed to fledge and was eventually euthanized by staff at Taronga Zoo. You can read about the 2015 breeding season here: It’s not easy for Powerful Owls.

IN 2016, they set off looking for “white wash”, the residue of Powerful Owl poo which paints the ground a distinct white and indicates their presence. Starting at the site of last year’s failed breeding they found nothing. It’s not unusual for Powerful Owls to abandon a site after a few failed attempts and it looked as if this pair may have moved on to another site. Unfortunately with the removal of old eucalypt trees from our urban landscapes, appropriate Powerful Owl sites are few and far between. They require very large hollows which only form in trees which are around 200 years old. However, there were a few large angophora trees with suitably sized hollows within the reserve. They inspected these trees but found nothing. It was starting to look as if the breeding season was over for this pair before it had started. Then on 26 July 2016, Chris (along with a volunteer from Birdlife Australia) went to search one last time.  Sitting beside a hollow which had been used in 2007 and 2010, they observed a single Powerful Owl.

Over the next few nights, it was confirmed that there was a breeding pair and on the 1 August the trilling of a chick from within the hollow was heard. Powerful Owls generally mate for life, but in this case it appeared that the female was trying her luck with a different male, most likely as a result of the past failures. Monitoring of the hollow continued over the following weeks, with a timeline of key observations below.

powerful-owl

Sunday 7 August 2016

The female Powerful Owl was observed delivering a Ringtail Possum to the owlet in the hollow. Ringtails are a favourite prey item, but Powerful Owl will also prey on Common Brush-tailed Possum, Flying-foxes and gliders.

Monday 8 August 2016

The chick was first seen peeping from the nest hollow.

Sunday 14 August 2016

powerful-owlsThe chick was observed stretching her wings from the edge of the hollow and making the trilling begging call (asking for food). 

Later that evening the female dropped in for a quick visit and to check on the owlet. Her plumage is visibly worn from entering and leaving the hollow. At this stage with the owlet now well insulated in down and new feathers, the female spends the warmer afternoons roosting nearby, keeping a watchful eye.

In the photo above you can see a feather from a Rainbow Lorikeet (Trichoglossus moluccanus) stuck to the talon of the owlet. This was a cause of some concern, as lorikeets, which are known prey item of Powerful Owls, are a vector of beak and feather disease (psittacine circoviral disease), which while mostly associated with parrots, has been known to infect Powerful Owls

Tuesday 16 August 2016

The owlet positioned itself on the edge of the hollow. Both parents sat on a tree nearby calling as if willing the young owl to take its first flight. The owlet remained on the hollow rim and eventually fell asleep.

Wednesday 17 August 2016

Success! The owlet took its first flight and became the first chick successfully fledged from the reserve in five years. Chris, who had spent many hours observing the pair, was not around at those final minutes and the crucial moment was also missed by the two infrared remote cameras, although he did catch the chick stretching and preparing for its first flight.

Fledgling (juvenile) Powerful Owls look very different to their parents. They have soft white plumage with dark streaks and eye patches. At about five months of age they have taken on their adult plumage.

Successful fledging is a huge milestone. But there are many more threats to overcome, including competition for hollows, predation by foxes and cats, prey-stealing by Ravens or Currawongs working as pairs, inappropriate fire regimes, road kill, interaction with overhead wires and barbed-wire fences.

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Wednesday 26 October 2016

Chris caught up with the owlet and it is looking strong and healthy.

Friday 11 November 2016

The owlet was again observed in a roost site looking strong and more and more grown-up. We wish this owlet success in finding a territory, a roost site and - when the time comes - a partner and an available nesting hollow. Thank you to Chris Charles, a local photographer who has been taking notes (and incredible photos) of the local Powerful Owls and sharing his observations for more than 10 years. You can see some of Chris’ other work at www.licole.com.au.

Figures

By Chris Charles

Figure 1 - a Powerful Owl chick at 3 months old already has an intimidating stare.

Figure 2 - a female Powerful Owl delivers a Ringtail Possum to the owlet in the hollow.

Figure 3 - a Powerful Owl chick is observed stretching her wings on 14 August.

Figure 4 - a female drops in for a quick visit to check on the owlet.

Figure 5 - the owlet moved to the edge of the hollow and fledging seemed imminent.

Figure 6 - the owlet looking healthy on 26 October. The adult pair was not observed.

Figure 7 - the last update on the owlet from 11 November.

Help us monitor the Owls

To get involved with protecting and recording sightings of the Powerful Owl in your area, visit Powerful Owl Project.

If you see or hear a Powerful Owl in the Ku-ring-gai Council area, please call 02 9424 0819 or send the record of your observation to Biobase@kmc.nsw.gov.au.